Coal auger bit



April 24', 1934.

W. E. POWELL COAL AUGER BIT Filed Dec. 17, .1932 3 Sheets-Sheet 1 @MM XW W. E. POWELL COAL AUGER BIT April 24, 1934.

Filed Dec. 17 1932 I 3 Sheets-Sheet 2 fr zz/enzr" Zflzlllz'czm EPOZ SZZ April 24, 1934.

Filed Dec] 17, 1952 w. E. POWELL 1,955,768

COAL AUGER B IT s Sheeis-Sheet s f'zz/enir ZZ/L'ZZz'czm EPoweQ' Patented Apr. 24, 1934 UNITED STATES PATENT OFFICE COAL AUGER BIT J. Skutt Application December 17, 1932, Serial No. 647,777

10 Claims. (Cl. 25561) My invention relates in general to auger bits and in particular to a self -feeding coal auger bit.

In mining coal at the present time a hole is first drilled in the particular deposit to be mined to a depth of possibly six feet. An explosive is then inserted in the hole and discharged, breaking up that particular portion so that the lump coal may be carried away. The holes are drilled by first setting up a post in the mine shaft securely anchored at top and bottom. An arm or grip is clamped to the post, said arm having a threaded split hole therein. An ordinary auger bit is used for boring the hole and this is fed forward into the coal by means of a threaded bar detachably secured to said auger bit, and inserted in the grip on the post. The thread bar is turned in the grip by the use of a hand brace, or like device. The bar is ordinarily made and threaded in a two foot length. As it is fed through to the end of the threads, the grip is pivotally opened and the bar started again at the beginning of the threads. Each time this is done the auger bit is withdrawn and a larger one substituted therefor, until the required depth in the hole is at- 5 tained. These operations require considerable time, and increase the total time required to drill the hole. In addition, such a method necessitates considerable equipment, cumbersome and bulky to handle.

An object of my invention is to provide an improved coal auger bit.

A further object is to provide a self-feeding coal auger bit.

A further object is to provide a sturdy, compact device for drilling holes in coal deposits, which device is ready for instant use.

A further object is to provide a coal auger bit having those parts which are most likely to become worn or broken, removable, so that it is not necessary to replace the entire device when only a portion requires replacement.

It is also an object of my invention to provide a coal auger bit especially adapted to be motor driven.

Other objects and advantages will appear as the description proceeds.

,Referring to the drawings:

Fig. 1 is a front elevation of an embodiment of my invention;

Fig. 2 is a side elevation of the device shown in Fig. 1;

Fig. 3 is an end view of the device looking in the direction of the arrows in Fig. 1;

Fig. 4 is a transverse view along the line 4-4 of Fig. 1;

Fig. 5 is a front elevation, partly in section, showing a modification of my invention;

Fig. 6 is a side elevation, partly in section, of the device of Fig. 5;

Fig. 7 is a transverse view along the line '77 of Fig. 5;

Fig. 8 is a transverse view along the line 88 of Fig. 5;

Fig. 9 is a side elevation of a further modification;

Fig..10 is a front elevation of the device of Fig. 9;

Fig. 11 is a transverse View along the line 11-11 of Fig. 9 and looking in the direction as shown by the arrows;

Fig. 12 is a side elevation of a further modification of my device having removable feeding threads;

Fig. 13 is a sectional view along the line 13-13 of Fig. 12; and

Fig. 14 is a side elevation of one of the removable thread sections of Fig. 12.

In the present invention I have provided an auger bit, self-feeding in itself, which does away with the post and grip, as well as the thread bar, thus decreasing the amount of necessary equipment, decreasing the operating time, and increasing the total efliciency of the apparatus.

The auger bit shown in Fig. 1 comprises a spiral pilot cutter 11, with a flat shank 12 adapted to fit into a slot in the lower end of a spiral shank 13 of the bit proper. A set screw 14 extends into a threaded aperture 15 in the bit and through an aperture in the shank 12 of the pilot cutter 11, detachably securing the pilot cutter in the bit.

The shank 13 of the bit proper is composed of spiralled channels 16 alternating with spiralled threaded portions 1'7 about the circumference of the shank. The threaded portions 17 taper outwardly and upwardly from the bottom, the degree of such taper determined by the particular coal into which the hole is to be drilled. The degree of taper increases as the coal becomes softer. Surmounting the shank of the bit is a split head 18, split to receive a coimter-bore cutter 19. A bolt 21 threaded on its end to receive a nut 22 extends through apertures in the two split sections of the head, and served to tighten said section onto the head'of a brace of extension shaft to which the bit is attached for boring into the coal. The counter-bore cutter 19 is narrower than the opening in the head 18 and is slidably held therein by the bolt 21 and the teeth '23 and 24 on either end thereof. The cutting edge on the tooth 23 is slightly below that on 24, and is set in slightly from the edge of the cutter. Tooth 24 on the other hand is adjacent that edge of the cutter 19.

In the use of my self-feeding auger bit, a hand brace or electric drill is provided having an auger of any desired length secured thereto. The auger bit in turn is detachably secured to the auger, preferably by clamping the end of said auger in the split portion of the head 18. The end of the auger may be flattened and an aperture drilled therein through which the bolt 21 is inserted, with said flattened portion extending down into the split portion of the head 18, and resting against the counter-bore cutter 19. A straight shaft may also be used in some instances in place of the auger.

Upon turning the auger or shaft in the drill the pilot cutter 11 cuts into the coal its entire depth, at which point the spiral threads cut into the coal and feed the auger bit therein. The inside of the hole is thus threaded the length of spiral threaded portion 17, until the counterbore 19 is in position to cut into the coal. With the bit moving in a clockwise direction, and the cutting edge of the tooth 23 slightly forward of the tooth 24, and set in from the edge, it cuts or reams out the thread in the coal and the tooth 24 completes the reaming operation by cutting deeper into the coal, in all enlarging the hole considerably beyond that cut by the shank 13 of the bit.

As the bit is fed into the coal by means of the threaded portions 17 on the shank, those pieces of coal cut away by the pilot cutter 11 and threaded spiral 17 are forced back through the spiral channels 16 coming out the top thereof adjacent the-head 18. This coal pushes the pieces reamed out by counter-bore cutter 19 as they accumulate, into the auger and the latter carries it out of the hole. The counter-bore cutter l9 shiftable in the split head 18 takes up any play in the auger secured directly in the electric drill or brace so that if the bit becomes slightly ofi center, neither the pilot cutter 11 nor the counter-bore cutter 19 will be broken by the turning of the shaft. With the pilot cutter 11 and counterbore 19 removably secured in the bit it is possible to detach same for the purpose of sharpening should the cutting edges on either piece become dulled in the drilling operation. They may also be quickly removed for the purpose of substituting new cutters therefor. This prolongs the life of the bit and reduces drilling costs, for these parts are ordinarily the only part of the bit which are broken in the normal drilling operation, and inasmuch as they are simple and inexpensive, may be replaced with relatively small expense. This is in contrast to the replacement of an entire auger bit of that type previously used in the case of the point being broken oil, or drilled and sharpened down to the place where it may no longer be resharpened.

As might be noted, with my device it is necessary to have only a single bit which may be secured to a hand brace or electric drill having a shaft thereon, or preferably an auger and with the use of this device, drill a hole to any desired depth in the coal in a single operation. It will not be necessary to remove the bit from the hole at any time until the completion thereof nor is it necessary to have the extensive apparatus required by earlier methods.

Figs. 5 to 8 illustrate a modification of my device in which the bit proper is composed of a casreesyes ing 53 having threads 57 about the outside surface thereof. Spiral slots 55 and 56 are cut in opposite sides of the casing 53. Spiral slot 55 extends from the lower edge of the casing and up approximately halfway to the top while the spiral slot 56 is cut into the casing on the opposite side and extends from approximately halfway up the casing to the top edge thereof. A pilot cutter 50 with cutting blades at a slight angle to each other is inserted in slots 51 and 52 cut in from the lower edge of the casing and at an angle with the horizontal to correspond with the shape of the pilot cutter 50. A lug 60 extends from one side of the pilot cutter 5c and adjacent one edge while an arm 61 is pivotally secured to the other side of the cutter by means of a pin 62. In inserting the pilot cutter 50 in the slots 51 and 52 in the lower edge of the casing, the movable arm 61 is set in a vertical direction such that the distance between the pin 62 upon which it is pivoted and that edge of the pilot cutter 50 is equal to approximately twice the width of the wall of the casing 53. The cutter 56 is then inserted in the slot 51 so that the pivotal arm abuts the inside of the casing adjacent that slot and is moved up into the casing to a position such that the opposite side of the cutter will fit into the slot 52 with the lug 60 abutt ng the inside of the casing adjacent that slot. The arm 61 is then pivoted into a horizontal position frictionallyvengaging the inside of the casing adjacent the slot 51. This pivotal arm is on the back of the cutter as the auger bit is moved in a clockwise direction. The cutter 50 is cut out in the two upper corners thereof so as to fit against the top of the slots 51 and 52 and against the inside of the casing as shown in Fig. 5. With the lug 60 and pivotal arm 61 abutting the inside of the casing and the pilot cutter 50 cut in at its two upper edges such pilot cutter is securely but detachably held in the casing 53 of'the auger bit. Casing 55 tapers from the bottom outwardly toward the top to a degree as is. desired for the particular coal into which the auger bit is being fed. A split head 58 bridges the top of the casing 53 so as to provide openings 63 and 64 through which the coal may pass as it is cut out by the pilot cutter and threads. A counter-bore cutter 65 substantially the same as counter-bore cutter 19 is slid-ably secured in the split portion of the head 58 in the same manner as heretofore described.

.In the operation of this modification the bit is secured to the shaft or auger in a brace or an electric drill as described in connection with the device shown in Fig. 1. The pilot cutter 50 cuts into the coal to its entire depth at which point the threads 57 on the outside of the casing 53 cut into the coal and feed the auger bit therein. In the same manner as described in connection with the device of Fig. 1 the counter-bore 65 reams out the threads and enlarges further the hole being drilled into the coal. The coal cut out by the pilot cutter 50 passes into the inside of the casing through openings 66 and 67 on the bottom of the bit, and through the spiral slots 55 and 56, passing out of the top of the casing through holes 63 and 64. With this form of the auger bit the effective threaded portion is almost double that of the device of Fig. 1 and thus will feed at a greater rate of speed at the same time of course increasing the speed at which the hole is being drilled.

A further modification of my invention is illustrated in Figs. 9 to 11. In this embodiment I provide a body portion 93 having a split lower porltd tion 94 and a split upper portion 95 substantially the same as the split head 18 of Fig. 1. There is a slot 96 extending upwardly from the lower portion 94, and a slot 97 extending downwardly from the top portion 95. The slots 96 and 97 are in planes at a right angle to one another, and extend over approximately three-quarters of the length upwardly and downwardly of the portions 94 and 95. In the assembly of the device a counter-bore cutter 98 is inserted in the lower slot 96. The cutter 98 has a body portion 99, the top of which rests against the top of the slot 96. On one side of the body 99 is the cutter 101, while on the other side is the cutter 102 having its cutting edge slightly above the cutting edge of cutter 101. The cutting edge of cutter 101 is shorter than the edge of cutter 102, due to the recessed portion 103 (Fig. 9) cut in the former. The outside edges 104 and 105 of the cutters are threaded over their entire length. The body portion 99 of the counter-bore cutter is cut out at its top so that the edges 106 and 107 extend above the top of the slot 96 and abut the sides of the bit thus preventing longitudinal movement of the cutter 98 in the slot. The counter-bore cutter 98 is held in the position described by a pilot cutter 111, having a flat shank 112, apertured therethrough for receiving a set screw 115, and adapted for inserting in the slot 96. The pilot cutter abuts the lower edge of the counterbore cutter 98 and is held in place in the body of the bit by the set screw 115 extending through said body and the shank 112. The pilot cutter 111 is also threaded over its outer edges 113 and 114.

A second counter-bore cutter 116 is provided for inserting in the upper slot 9'7. This like counter-bore cutter 98, has cutters 117 and 118 on either side with the cutting edge on cutter 118 slightly below that of cutter 117 and the cutting edge of the latter shorter due to the recessed portion 119. The cutter 116 rests against the bottom of the slot 97 and is held from longitudinal movement, by the edges 120 and 121 of the cut-in portion of the body of the cutter abutting the sides of the upper portion 95 of the auger bit. Vertical movement of the counter-bore cutter 116 is prevented by the auger or shaft fitting down over same and held in the bit by the bolt 122 in the same manner as described in the aforementioned embodiments of my invention.

In the use of the auger bit it is detachably secured to an auger or shaft which in turn is attached to a hand brace or electric drill in the manner heretofore described. In the drilling operation the lower edges of the pilot cutter 111 cut into the coal and the threaded edges 113. 114 out further therein, gripping the coal and feeding the bit and auger forward. With the bit moving in a clockwise direction the cutter portion 101 of the counter-bore cutter 98 engages the coal, and reams or bores out the threads cut by the pilot cutter 111, and a portion greater than that, determined by the particular coal being mined. The width of the counter-bore cutters is determined by the coal being mined, with the width increasing in the softer coal. The cutting edge of cutter 102 being slightly above that of cutter 101, and longer, will follow the path of the latter boring out an additional amount of coal. The threaded edges 104 and 105 out into the coal and aid in feeding the bit into the coal. The reaming or boring is completed by the counter-bore cutter 116 operating in the same manner as counter-bore cutter 98 and enlarging the hole in the coal a proportionate amount. The

coal cut by the bit is carried back on to the auger and out of the hole by the bit and auger turning therein. 7

Any one or all of the counter-bore cutters. and the pilot cutter may be removed for the purpose of sharpening, or they may be quickly substituted in the event they are broken or worn beyond further use.

A further embodiment of my invention is illustrated in Figs. 12 to 14 in which a coal auger bit is provided having a body 121, and a split head 122 with a slot 123 therein. A counter-bore cutter 124 similar to cutter 19 is adapted to fit in the slot 123 and is slidably held therein by a threaded bolt 126 extending through the two split portions of the head. A pilot cutter 127 is adapted to fit in a slot 128 at the lower end of the body 121 in a manner similar to the pilot cutter of Fig. 1, and removably secured by a set screw 129.

It has been found that the feed threads on the auger bit Wear with continued use so as to require sharpening at intervals during the life of the bit. In the embodiment of Fig. 12, delay caused by the sharpening operation is obviated by a replaceable thread section 131 fitting in a cavity 132 formed in the raised portion 133 on the surface of the bit. The appropriate thread section has been left out of the cavity 132a in Fig. 12 to illustrate the construction of said cavity. In the device of Fig. 12, four raised portions are provided on the surface of the bit separated by spiral channels 134. Each of the raised portions 133 has a similar cavity therein for receiving a threaded section, and although four such portions have been illustrated, it is understood that this number may be varied. The threads on each section 131 taper progressively over the four removable sections so as to provide a continuous feeding thread for the entire bit. A different replacement section is thus required for each cavity. The thread sections may be retained in the cavities by set screws 136 on any other suitable means.

With the embodiment of Fig. 12, it is thus apparent that all of those portions on the auger bit, viz., pilot cutter, feeding threads, and counter-bore cutter, which may either break or wear with use, may be readily replaced with consequent saving in cost over the situation where an entire auger becomes useless upon the breaking or wearing of one of its integral parts.

It is to be understood that the embodiments of the invention herein described and disclosed are merely convenient and useful forms of the invention and that other modifications and changes may be made without departing from the spirit and scope of the invention.

What I claim as new and desire to protect by United States Letters Patent is:

1. A self-feeding coal auger bit comprising a tapered body portion having threads thereon adapted for cutting into the coal and feeding the bit therein, a pilot cutter at one end of the body portion for initially cutting into the coal, an integral split head at the other end of the body, a counterbore cutter carried in the split portion of the head for reaming out the hole cut by the threaded portion whereby an enlarged hole is provided to permit ready removal of the bit from the coal.

2. A self feeding coal auger'bit comprising a tapered body portion having threads thereon adapted for cutting into the coal and feeding the bit therein, a pilot cutter detachably secured in one end of the body portion for initially cutting into the coal, an integral split head at the other end of the body, and a counter-bore cutter carried slidably in the split portion of the head for reaming out the hole cut by the threaded portion, whereby an enlarged hole is provided to permit ready removal of the bit from the coal.

3. A self-feeding coal auger bit comprising a tapered body portion including alternate spiralled channels, and spiralled threaded portions about the surface thereof with said threaded portions adapted for cutting into the coal and feeding the bit therein, a pilot cutter detachably secured in one end of said body portion for initially cutting into the coal, an integral split head at the other end of the body, and a counterbore cutter carried slidably in the split portion of the head for reaming out the hole cut by the threaded portion whereby an enlarged hole is provided to permit ready removal of the bit from the coal.

4. A self-feeding coal auger bit comprising a tapered body portion including a hollow casing, threads extending over substantially the entire surface of said casing and adapted to feed the bit into the coal upon the turning of the same, a pilot cutter detachably secured to one end of said casing for initially cutting into the coal, a split head bridging the other end of the casing, and a counter-bore cutter secured in the split portion of the head of greater width than the largest diameter of the casing, with said cutter adapted for reaming out the hole cut by the threaded portion whereby an enlarged hole is provided to permit ready removal of the bit.

5. A self-feeding coal auger bit comprising a tapered body portion including a hollow casing threaded over substantially its entire casing to feed the bit into the coal upon the turning of the same, openings at either end, a pilot cutter detachably secured in the lower opening, a split head bridging the upper opening of the body portion, and means on the sides of the casing for carrying coal into the inside of the casing to be in turn carried through the upper opening and out through the hole in back of the bit, and a counter-bore cutter secured in the split portion of the head for reaming out the hole cut by the threaded portion, whereby an enlarged hole is provided to permit ready removal of the bit from the coal.

6. A self-feeding coal auger bit comprising a tapered body portion having a pilot cutter detachably secured to one end, and a counter-bore cutter carried at the other end of said body portion, and a plurality of threaded sections removably secured in said Edy portion with said threads adapted to cut corresponding threads in the coal for feeding the bit therein.

7. A self-feeding coal auger bit adapted for drilling holes in coal deposits comprising a ta pered body portion having channels and removable thread sections alternately spaced about the surface thereof, with said threads adapted to cut corresponding threads to feed the bit into the coal, a pilot cutter detachably secured in one end of the body portion adapted to precede said body into the coal, and a counterbore cutter slidably secured in the other end thereof for reaming out the hole cut by the threaded portion whereby an enlarged hole is provided to permit ready removal of the bit from the coal.

8. A self-feeding coal auger bit adapted for drilling holes in coal deposits, with said bit comprising a comparatively short tapered body portion, a plurality of alternate spiralled threaded and channelled portions over the surface thereof, a spiralled pilot cutter removably secured to one end of the body portion and adapted to precede the body portion into the coal, with said threaded portions adapted to cut corresponding threads in the coal to feed the bit therein, and a counter-bore cutter slidably carried at the other end of the body portion to finally ream out the hole cut in the coal to enlarge the same to permit ready removal of the bit from the coal.

9. A self-feeding coal auger bit adapted for drilling holes in coal deposits, with said bit comprising a tapered body portion including alternate spiralled channels and spiralled threaded portions about the surface thereof, a pilot cutter secured to the body portion and adapted to precede said body portion into the coal, the tapered threaded portion of the body adapted to form a corresponding thread in the hole and feed the bit forwardly therein, a head on said body, and a counter-bore cutter slidably carried by the head having means for initially reaming a portion of the hole approximately the depth of the threads, and a second reaming portion on said counterbore cutter positioned to subsequently further ream the inside of the hole to provide an enlarged hole to permit ready removal of the bit'from the coal.

10. A self-feeding coal auger bit adapted for drilling holes in coal deposits, comprising a body portion having a tapered threaded portion on the outer surface thereof to cut corresponding threads in the hole in the coal to feed the bit forwardly therein, a split head on the body portion and a counterbore cutter carried in the head having cutting means for initially reaming a portion of the hole slightly greater than the depth of the threads and a second cutting portion on said counter-bore cutter positioned to subsequently further ream the inside of the hole to provide an enlarged hole to permit ready removal of the bit from the coal.

WILLIAM E. POWELL. 

